Preventive cancer vaccine based on brother of regulator of imprinted sites molecule (boris)

ABSTRACT

Polynucleotides encoding a nonfunctional mutant form of the Brother of Regulator of Imprinted Sites (BORIS) molecule, nonfunctional mutated BORIS protein, polypeptide or peptide and modified protein forms of BORIS are described. These molecules are used as a therapeutic vaccine against cancer.

CROSS REFERENCES TO RELATED APPLICATIONS

This application is a Divisional of co-pending application Ser. No. 10/569,907, filed on Feb. 27, 2006, which is a National Phase under 35 U.S.C. §371 of PCT International Application No. PCT/US2004/027856 which has an International filing date of Aug. 25, 2004, which designated the United States of America and on which priority is claimed under 35 U.S.C. §120, the entire contents of which are hereby incorporated by reference. This Divisional application claims priority under 35 U.S.C. §119(e) on U.S. Provisional Application No. 60/497,511 filed on Aug. 25, 2003, the entire contents of which are hereby incorporated by reference.

FIELD OF THE INVENTION

The present invention relates to compositions and methods used for the generation of a tumor vaccine.

BACKGROUND

Vertebrates possess the ability to mount an immune response as a defense against pathogens from the environment as well as against aberrant cells, such as tumor cells, which develop internally. The immune response is the result of complex interactions between a variety of cells and factors, but generally comprises two main facets. One is a cellular component, in which specialized cells directly attack an offending agent (bearing an antigen) while the other is a humoral component, in which antibody molecules bind specifically to the antigen and aid in its elimination. Acting in concert, the individual elements are quite effective in limiting the initial onslaught of invading pathogens and eliminating them from the host.

The primary cells involved in providing an immune response are lymphocytes, which generally comprise two principal classes. The first of these, designated B cells or B lymphocytes, are typically generated in bone marrow and are, among other duties, responsible for producing and secreting antibodies. B cell antibody products tend to react directly with foreign antigens and neutralize them or activate other components of the immune systems that then eliminate them. In particular, opsonizing antibodies bind to extracellular foreign agents thereby rendering them susceptible to phagocytosis and subsequent intracellular killing. On the other hand, T cells or T lymphocytes, which generally develop or mature in the thymus, are responsible for mediating the cellular immune response. These cells do not recognize whole antigens but, instead, respond to short peptide fragments thereof bound to specialized proteins that appear on the surface of the surface of a target cell as well as an antigen presenting cell. More particularly, it appears that proteins produced within the cell, or taken up by the cell from extracellular milieu, are continually degraded to peptides by normal metabolic pathways. The resulting short fragments associate with intracellular major histocompatibility complex (MHC) molecules and the MHC-peptide complexes are transported to the surface of the cell for recognition by T cells. Thus, the cellular immune system is constantly monitoring a full spectrum of proteins produced or ingested by the cells and is posed to eliminate any cells presenting foreign antigens or tumor antigens; i.e. virus infected cells or cancer cells.

The structure of immunoglobulin G (IgG) is that of a tetrameric protein complex comprising two identical heavy (H) chains and two identical immunoglobulin light (L) chains. These chains are joined together by disulfide bonds to form the Y-shaped antibody complex. In solution however, the molecule takes on a more globular shape and readily bind to foreign antigens present in biological fluids Amino acid sequence analysis of immunoglobulins has led to the definition of specific regions with various functional activities within the chains. Each light chain and each heavy chain has a variable region (V_(L) and V_(H) respectively) defined within the first 110 amino terminal residues. Three dimensional pairing of the V_(L) and V_(H) regions constitute the antigen-recognition portion or “antigen combining site” (“ACS”) of immunoglobulin molecule. Because of the tetrameric nature of immunoglobulins, there are two identical antigen combining sites per molecule. The variable domains of these chains are highly heterogeneous in sequence and provide the diversity for antigen combining sites to be highly specific for a large variety of antigenic structures. The heterogeneity of the variable domains is not evenly distributed throughout the variable regions, but is located in three segments, called complementarity determining regions (“CDRs”) designated CDR 1, CDR 2 and CDR 3. For further information regarding these structures see Watson et al., 1987, Molecular Biology of the Gene, Fourth Edition, Benjamin/Cummings Publishing Co., Inc. Menlo Park, Calif. incorporated herein by reference.

Each of the heavy chains also includes a constant region defining a particular isotype and assigns the immunoglobulin to one of the immunoglobulin classes and subclasses. The constant region contains units called domains (i.e. C_(H1), C_(H2), etc.) that do not vary significantly among antibodies of a single class. The constant region does not participate in antigen binding, but can be associated with a number of biological activities known as “effector functions”, such as binding to Fc receptors on cell surfaces as well as binding to complement proteins. Antigen presenting cells such as dendritic cells and macrophages are, among other features, generally distinguished by the presence of an Fc receptor. Consequently, if an antibody is bound to a pathogen, it can then link to a phagocyte via the Fc portion. This allows the pathogen to be ingested and destroyed by the phagocyte, a process known as opsonization. Moreover, as will be discussed in more detail below, various pathogenic antigens may be processed and displayed by the APC to further stimulate an immune response.

Unlike the heavy chains, the light chains have a single constant domain (C_(L)). A light chain pairs with a heavy chain through a disulfide bond which attaches heavy constant region C_(H1) to C_(L). In addition, the heavy chains have a hinge region separating constant regions C_(H1) and C_(H2) from the remainder of the molecule. It is this hinge region that is largely responsible for the flexibility of the tetramer. The two heavy chains of the molecule pair together through disulfide bonds at the junction between the hinge region and C_(H2).

In order to provide such an extensive repertoire, immunoglobulin genes have evolved so as permit the production of vast numbers of different immunoglobulin proteins from a finite number of genes i.e. inherent polymorphism. Due to inherent polymorphism, mammals are able to produce antibodies to a seemingly infinite variety of antigens. For a review of immunoglobulin genetics and protein structure see Lewin, “Genes III”, John Wiley and Sons, N.Y. (1987) and Benjamini and Leskowitz, 1988, Immunology, Alan R. Liss, Inc., New York, which is incorporated herein by reference.

In the past few years antibodies have become extremely important in diagnostic and therapeutic applications due to their diversity and specificity. Increasingly, molecular biology techniques have been used to expand the variety and availability of antibodies for scientific applications. For instance, a single antibody producing B cell can be immortalized by fusion with a tumor cell and expanded to provide an in vitro source of antibodies of a single specificity known as a “monoclonal antibody” (mAb). Such an immortal B cell line is termed a “hybridoma.”

Until recently, the source of most mAb has been murine (mouse) hybridomas cultured in vitro. That is, a mouse was typically injected with a selected antigen or immunogen. Subsequently, the animal was sacrificed and cells removed from its spleen were fused with immortal myeloma cells. Although they have been used extensively in diagnostic procedures, murine mAb are not well suited for therapeutic applications in most mammals including humans. In part, this is due to the fact that murine antibodies are recognized as foreign by other mammalian species and elicit an immune response that may itself cause illness.

To overcome at least some of the problems of immune responses generated by foreign mAb and the lack of suitable human mAb, genetic engineering has been used to construct humanized chimeric immunoglobulin molecules which contain the antigen binding complementarity determining regions of the murine antibodies but in which the remainder of the molecule is composed of human antibody sequences which are not recognized as foreign. Such antibodies have been used to treat tumors as the mouse variable region recognizes the tumor antigen and the humanized portion of the molecule is able to mediate an immune response without being rapidly eliminated by the body. See, for example, Jones et al., Nature, 321:522-525 (1986), which is incorporated herein by reference.

Other uses of such antibodies are detailed in PCT Publication No. WO 94/14847, which is also incorporated herein by reference. In these cases epitopes of foreign antigens such as viral or bacterial epitopes are grafted onto the hypervariable region of an immunoglobulin to induce a response. That is, the engineered antibodies are used as a vaccine to provoke an immune response and confer long-term immunogenic memory thereby allowing the subject to fight off subsequent infections.

These and more traditional vaccines are effective in that they stimulate both prongs of the immune system. Despite the intricacies associated with the humoral component of the immune response, it would not, in and of itself, be capable of effectively protecting an animal from the myriad pathogenic assaults to which it is subject each day. Rather, it is only the presence of a highly evolved cellular response that allows higher organisms to survive and proliferate.

As indicated above, T lymphocytes or T cells, which arise from precursors in the bone marrow, are central players in the immune response against invading viruses and other microbes. The progenitor stem cells migrate to the thymus where, as so-called thymocytes, they become specialized. In particular, they begin to display the receptor molecules that later enable mature T cells to detect infection. To be beneficial, T cells must be able to attach through their receptors to antigens (protein markers signaling an invader's presence). At the same time, they should be blind to substances made by the body as self-reactive T cells can destroy normal tissues. Typically, only those thymocytes that make useful receptors will mature fully and enter the bloodstream to patrol the body. Others that would be ineffectual or would attack the body's own tissue are, in healthy individuals, eliminated through apoptosis prior to leaving the thymus.

Mature T cells that finally enter the circulation, either as cytolytic T lymphocytes or T helper cells, remain at rest unless they encounter antigens that their receptors can recognize. Upon encountering the specific antigens for which the lymphocytes have affinity, they proliferate and perform effector functions, the result of which is elimination of the foreign antigens.

T cells have been classified into several subpopulations based on the different tasks they perform. These subpopulations include helper T cells (T_(h)), which are required for promoting or enhancing T and B cell responses; cytotoxic (or cytolytic) T lymphocytes (CTL), which directly kill their target cells by cell lysis; and suppressor or regulatory T cells (T_(s) or Tr) which down-regulate the immune response. In every case T cells recognize antigens, but only when presented on the surface of a cell by a specialized protein complex attached to the surface of antigen presenting cells. More particularly, T cells use a specific receptor, termed the T cell antigen receptor (TCR), which is a transmembrane protein complex capable of recognizing an antigen in association with the group of proteins collectively termed the major histocompatibility complex (MHC). Thousands of identical TCR's are expressed on each cell. The TCR is related, both in function and structure, to the surface antibody (non-secreted) which B cells use as their antigen receptors. Further, different subpopulations of T cells also express a variety of cell surface proteins, some of which are termed “marker proteins” because they are characteristic of particular subpopulations. For example, most T_(h) cells express the cell surface CD4 protein, whereas most CTL cells express the cell surface CD8 protein and Tr cells expressed CD25 and CD4 molecules. These surface proteins are important in the initiation and maintenance of immune responses that depend on the recognition of, and interactions between, particular proteins or protein complexes on the surface of APCs.

For some time it has been known that the major histocompatibility complex or MHC actually comprises a series of glycosylated proteins comprising distinct quaternary structures. Generally, the structures are of two types: class I MHC which displays peptides from proteins made inside the cell (such as self-proteins or proteins produced subsequent to viral replication), and class II MHC, which generally displays peptides from proteins that have entered the cell from the outside (soluble antigens such as bacterial toxins). Recognition of various antigens is assured by inherited polymorphism that continuously provides a diverse pool of MHC molecules capable of binding any pathogenic peptides that may arise. Essentially, all nucleated cells produce and express class I MHC, which may exhibit naturally occurring peptides, tumor associated peptides or peptides produced by a viral invader. Conversely, some other nucleated cells and among them specialized lymphoid cells, those generally known as antigen presenting cells, produce and express class II MHC proteins. Regardless of the cell type, both classes of MHC carry peptides to the cell surface and present them to resting T lymphocytes. Ordinarily, T_(h) cells recognize class II MHC-antigen complexes while CTL's tend to recognize class I MHC-antigen complexes, although cross-presentation of antigens also occurred

When a resting T cell bearing the appropriate TCR encounters the APC displaying the peptide on its surface, the TCR binds to the peptide-MHC complex. More particularly, hundreds of TCR's bind to numerous peptide-MHC complexes. When enough TCRs are contacted the cumulative effect activates the T cell. Receptors on T cells that are responsible for the specific recognition of, and response to, the MHC-antigen complex are composed of a complex of several integral plasma membrane proteins. As with the MHC complex previously discussed, a diverse pool of TCR's is assured by inherent polymorphism leading to somatic rearrangement. It should be emphasized that, while the pool of TCR's may be diverse, each individual T cell only expresses a single specific TCR. However, each T cell typically exhibits thousands of copies of this receptor, specific for only one peptide, on the surface of each cell. In addition, several other types of membrane associated proteins are involved with T cell binding and activation.

Activation of the T cell entails the generation of a series of chemical signals (primarily cytokines) that result in the cell taking direct action or stimulating other cells of the immune system to act. In the case of class I MHC-antigen activation, CTL's proliferate and act to destroy infected cells presenting the same antigen Killing an infected cell deprives a virus of life support and makes it accessible to antibodies, which finally eliminate it. In contrast, activation of T_(h) cells by class II MHC-antigen complexes does not destroy the antigen presenting cell (which is part of the host's defense system) but rather stimulates the T_(h) cell to proliferate and generate signals (again primarily cytokines) that affect various cells. Among other consequences, the signaling leads to B cell stimulation, macrophage activation, CTL differentiation and promotion of inflammation. This concerted response is relatively specific and is directed to foreign elements bearing the peptide presented by the class II MHC system.

Constant surveillance of epitopes throughout those structures in the body accessible to the immune system provides a very effective means for recognizing and maintaining “self” and destroying epitopes and their carriers that invade the body or arise pathologically. When operating properly the immune response is surprisingly effective at eliminating microscopic pathogens and neoplastic (tumor) cells that are believed to arise continuously in the body and for the most part are eliminated by the immune system before becoming detectable. Certain regions of the body, such as the brain, eye, and testis, are protected from immune surveillance, these sites are referred to as immune privileged. In general, the complicated mechanisms for self-recognition are very efficient and allow a strong response to be directed exclusively at foreign antigens. Unfortunately, the immune system occasionally malfunctions and turns against the cells of the host provoking an autoimmune response. Typically, autoimmunity is held to occur when the antigen receptors on immune cells recognize specific antigens on healthy cells and cause the cells bearing those particular substances to die. In many cases, autoimmune reactions are self-limited in that they disappear when the antigens that set them off are cleared away. However, in some instances the autoreactive lymphocytes survive longer than they should and continue to induce apoptosis or otherwise eliminate normal cells.

Current data indicates that immune protection against all cancers requires the generation of a potent cellular immune responses against a unique tumor antigen expressed by the malignant cell. As a consequence, successful immune protection first requires a unique antigen expressed in the tumor cells (tumor-specific antigen) and second, induction of a potent T cell immune response targeted to the tumor antigen.

Several tumor-associated antigens are currently known, and have been used in pre-clinical and clinical studies for generating vaccines. For example, PSMA, PAP and PSA are antigens expressed in prostate tumor cells. Her2/neu and MUC1 are antigens expressed by breast cancer cells and other carcinomas, including carcinomas of the lung, ovary, colon, and pancreas. MAGEs and MART-1 are melanoma tumor cell-associated antigens, and CEA is an antigen associated with pancreas or colorectal cancer. Other tissue and/or tumor specific antigens also have been described. However, while all of these antigens are expressed in tumor cells in the normal or aberrant forms, they are also expressed in a variety of normal cells, and thus cannot be used for prophylactic vaccination. In other words, these tumor-associated antigens are still recognized by immune cells as self-molecules and so no true activation of the immune system occurs. This presents at least two obstacles for targeting these tumor-associated molecules as the basis for a vaccine. The first obstacle is the unresponsiveness (tolerance) of the immune system to self-molecules, which restricts its ability to generate potent cellular immune responses. The second is that any potent cellular immune response generated should not be directed toward normal cells that express the target antigen. This is the reason that all the tumor-associated antigens discussed above are suggested for use only as targets for therapeutic vaccinations.

A new protein has been recently described that is able to overcome the problems associated with the known tumor-associated antigens. Brother of Regulator of Imprinted Sites (BORIS) was first described as a DNA-binding protein found in testis. This protein shares 11 zinc-finger (ZF) domains with CCCTC-binding factor (CTCF) that is a multivalent 11-zinc finger nuclear factor. CTCF is a conserved, ubiquitous and highly versatile factor involved in various aspects of gene regulation and which forms methylation-sensitive insulators that regulate X chromosome inactivation and expression of imprinted genes. BORIS differs from CTCF, however, at the N and C termini and is expressed in a mutually exclusive manner with CTCF during male germ cell development. BORIS expression is restricted to the testis and then only within a select cell subpopulation of spermatocytes that are involved with the re-setting of methylation marks during male germ cell development. This testis cell subpopulation is also the only normal cell type known that does not express CTCF. Because inhibition of CTCF expression in cultured cells leads to apoptosis, it is reasonable to assume that BORIS is activated to maintain some of the vital CTCF functions in testis cells (Loukinov et al. (2002) Proc. Natl. Acad. Sci. 99(10):6806-6811; which is incorporated herein by reference).

More recently, it was demonstrated that while CTCF overexpression also blocks cell proliferation, expression of BORIS in normally BORIS-negative cells promotes cell growth that can lead to transformation (Klenova et al. (2002) Cancer Biol. 12:399-414; which is incorporated herein by reference). Human BORIS maps to the 20q13 region, which is well known for frequent gains and/or amplifications observed in many of the same types of tumors that also often show loss of heterozygosity (LOH) at the paralogous locus on 16q22 where CTCF resides. These regions are associated with “hot-spots” associated with breast, prostate, ovarian, gastric, liver, endometrial, glioma, colon and esophageal cancer as well as Wilms tumors. Importantly, abnormal activation of BORIS expression appears to be found in a significant proportion of a wide variety of neoplasms. Using Northern blots or RT-PCR, Klenova et al. (2002) analyzed BORIS mRNA levels in over 200 cancer cell lines representing most of the major forms of human tumors and detected transcripts in more than one half of the cell lines tested. Subsequent analysis of primary cancers, for breast cancer samples, confirmed the results obtained with the cell lines.

SUMMARY OF THE INVENTION

The present invention is directed to nonfunctional mutant polynucleotides encoding the Brother of Regulator of Imprinted Sites (BORIS) tumor antigen and the use of such polynucleotides for preventive vaccination and immunotherapy of primary or metastatic cancer. The polynucleotide may be either DNA or RNA. In one preferred embodiment, the tumor antigen is a non-functional mutated form of the BORIS molecule lacking DNA binding capability. In another preferred embodiment at least one zinc finger (ZF) domain is nonfunctional due to mutation or deletion and the function of BORIS is eliminated. In another preferred embodiment any combination of the zinc finger domains are mutated or deleted and function of the BORIS protein, polypeptide or peptide is eliminated. In yet another preferred embodiment all of the ZF binding sites are deleted. In still another preferred embodiment the polynucleotide encoding the mutated form of BORIS is fused to a molecular adjuvant. In still another preferred embodiment the polynucleotide encoding the nonfunctional mutated form of BORIS is mixed with at least one other polynucleotide encoding a molecular adjuvant. Any molecular adjuvant that increases cellular immune response can be used. Cytokines, chemokines and co-stimulatory molecules are particularly preferred. Particularly preferred chemokines, cytokines and co-stimulatory molecules are beta-defensin2, Il12, IL18, MIPα3, IFNγ and CD80/86.

The present invention is also directed to a vector comprising a polynucleotide encoding a nonfunctional mutated form of BORIS. In a preferred embodiment the vector directs expression in a bacterial, mammalian, yeast cell or viral system.

The present invention is further directed to a nonfunctional modified (mutant) form of a BORIS protein, polypeptide or peptide. The nonfunctional mutant can be made using any method that introduces deletions, substitutions or additions in the sequence that result in a non-functional protein. In a preferred embodiment the mutant BORIS protein, polypeptide or peptide lacks DNA binding ability. In another preferred embodiment the mutant BORIS protein, polypeptide or peptide is mixed with conventional adjuvant. In yet another preferred embodiment the nonfunctional mutant BORIS protein, polypeptide, or peptide is attached to a pharmaceutically acceptable carrier (backbone). In still another preferred embodiment the nonfunctional mutant BORIS protein, polypeptide or peptide is attached to a peptide that modifies BORIS and retains it antigenic property. In yet another preferred embodiment the nonfunctional mutant BORIS protein, polypeptide or peptide is attached to a protein transducing domain (PTD).

The present invention is also directed to dendritic cells expressing a nonfunctional mutant BORIS molecule. In a preferred embodiment the dendritic cells are transfected with DNA encoding a mutant BORIS molecule. In yet another preferred embodiment the dendritic cells are infected with a viral vector that encodes a nonfunctional mutant BORIS molecule. In yet another preferred embodiment the dendritic cells are loaded with nonfunctional mutant BORIS protein, polypeptide, peptide or any nonfunctional modified protein form of BORIS.

The present invention encompasses cellular immune responses generated against a nonfunctional mutant form of the BORIS protein, polypeptide, peptide or any nonfunctional modified protein form of BORIS. The present invention encompasses antibodies raised against a nonfunctional mutant form of the BORIS protein, polypeptide, peptide or any modified protein form of BORIS.

The present invention also encompasses a cancer preventive or therapeutic vaccine comprising a polynucleotide encoding a nonfunctional mutant form of BORIS, a nonfunctional mutant BORIS protein, polypeptide or peptide or dendritic cells expressing a nonfunctional mutant BORIS molecule.

The present invention is also directed towards a method of treating cancer comprising administering to a patient (prophylactic vaccine) in need thereof an effective amount of a polynucleotide encoding a nonfunctional mutant form of BORIS, a nonfunctional mutant BORIS protein, polypeptide or peptide, or dendritic cells expressing or containing a nonfunctional mutant BORIS molecule. Administration can be via an intramuscular, subcutaneous, intradermal, intravenous, nasal, rectal, vaginal or peritoneal route. The cancer can be a primary or metastatic cancer. The patient can have multiple different types of cancer. In a preferred embodiment the cancer is breast, prostate, ovarian, gastric, liver, endometrial, glioma, colon, or esophageal cancer.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1 a, b, and c present the results of vaccination of mice (n=10) with pBORIS (DNA immunization) pIL12/IL18 (molecular adjuvant). This resulted in protection of mice from challenge with 10⁴ 4T1 tumor cells naturally expressing mouse BORIS. FIG. 1 a shows survival rate on the Y axis and Days after tumor challenge on the X axis for pBORIS/pIL12/IL18, pIL12/IL18 and vector only. FIG. 1 b show the relationship between tumor volume and days after tumor challenge for pBORIS/pIL12/IL18, pIL12/IL18 and vector only. FIG. 1 c shows the significant difference in tumor volume at day 21 between groups immunized with pBORIS/pIL12/IL18 vs. pIL12/IL18 and vector only (* P<0.001).

FIG. 2 a and b show the relationship between percent survival and days after tumor challenge (a) and tumor volume and days after challenge for mice vaccinated with pBORIS (DNA immunizations) followed by Ad5-BORIS (viral like particles) and challenged with 10⁴ 4T1 cells. Data demonstrated a full protection against the tumor challenge after al least 33 days of challenge.

FIG. 3 a, b, c present the results of gene-gun immunization of mice with pBORIS plus pIFNγ or pIL12/IL18 followed by challenge with 10⁵ 4T1 tumor cells. FIG. 3 a shows a prolonged time of tumor growth to the volume of 2 cm³ and FIG. 3 b shows a lower the tumor growth rate. FIG. 3 c shows significant differences in tumor volume at day 14 between groups pBORIS/pIFNγ vs. vector (p<0.05), pBORIS/pIL12/IL18 vs. pIL12/IL18 (P<0.05) and pBORIS/pIL12/IL18 vs. vector (P<0.01).

FIG. 4 a, b, and c show the results of mice vaccinated with pBORIS (DNA immunization) followed by injection of Ad5-BORIS (viral like particles). FIG. 4 a shows a significantly prolonged survival of the vaccinated mice while FIG. 4 b shows that these mice had a lower the tumor growth rate and prolonged the time of tumor growth to the volume of 2 cm³ after challenge of mice with 10⁵ 4T1 tumor cells. FIG. 4 c shows a significant difference in tumor volume at day 15 between groups Ad5-BORIS vs. Ad5 (P<0.001).

FIG. 5 shows the best-fit alignment of the human (bottom sequence-SEQ ID NO: 2) and mouse (top sequence-SEQ ID NO: 4) BORIS polypeptides produced by the GCG-package of programs with zero-penalty for the gap extension with conserved zinc finger regions highlighted and indicated as ZF-11.

FIG. 6 shows detection of expression of pShuttle-BORIS in CHO by immunoblotting.

FIG. 7 shows purification of ZF-deleted BORIS from E. coli BL21(DE3). Protein is analyzed by 10% SDS-PAGE. The same data (not shown) is generated with BORIS fused with PTD.

DETAILED DESCRIPTION OF THE INVENTION

While the present invention may be embodied in many different forms, specific illustrative embodiments are disclosed herein that exemplify the principles of the invention. It should be emphasized that the present invention is not limited to the specific embodiments illustrated.

The present invention involves the use of an antigen expressed only in immune-privileged testis cells and appearing in many transformed tumor cells to prevent a tolerating effect, which may induce other tumor antigens. The invention also involves the introduction of specific changes in the DNA encoding the antigen to eliminate side effects and autoimmune reactions. In this context the following definitions apply.

The terms “tumor,” “cancer,” “neoplasm,” “neoplasia” and their etymological relatives are used interchangeably in the context of this application to refer generally to dysproliferative diseases and the attendant affected cells or cell masses. Preferably, the dysproliferative cells referred to herein express an immune-privileged antigen.

Cytotoxic T lymphocytes (CTLs) are effector T cells, usually CD8+ that can mediate the lysis of target cells bearing antigenic peptides associated with a MHC molecule. Other cytotoxic cells include gamma/delta and CD4+ NK 1.1+ cells.

Immune privilege and immune-privileged antigen refer to the isolation of certain sites and antigens within the body from the immune system and thus relate to antigens to which an immune response is not normally developed. Immune-privileged antigens expressed ectopically (i.e., outside of their normally immune-privileged sites) may result in autoimmunity or tumor immunity. Immune-privileged antigens are expressed by some tumors resulting in an immune response to both the tumor and to non-tumor sites expressing the same immune-privileged antigens.

Antigen presenting cells (APCs) are cells including dendritic cells, macrophages, and B cells, that can process and present antigenic peptides in association with class I or class II MHC molecules and deliver a co-stimulatory signal necessary for T cell activation.

A “zinc finger domain” refers to a small independently folded domain that requires coordination of one or more zinc ions to stabilize its structure. Fingers bind to three base pair subsites and specific contacts are mediated by amino acids in positions −1, 2, 3 and 6 relative to the start of the alpha helix.

A “nonfunctional mutant form of BORIS” refers to a BORIS protein, polypeptide or peptide that lacks function. “Lack of function” is intended to mean failing to perform any one of the critical activities of the wildtype BORIS molecule such as DNA binding, re-establishment of the paternal DNA-methylation pattern, etc.

“Nonfunctional mutant” refers to changes at the DNA or amino acid level that destroy the wildtype activity of the resulting protein. Such changes can be amino acid substitutions, deletions or additions in areas of the molecule that act as catalytic sites and/or participate in binding DNA or protein. Examples of changes that are able to destroy activity are deletions or substitutions of critical amino acids participating in a catalytic or binding interaction, additions of amino acids that alter the required three dimensional structure of the site involved in catalytic and/or binding interactions, or additions or deletions of nucleotides that cause frame shifts, thus destroying the required three dimensional structure. Mutations can be produced using common molecular techniques such as PCR, use of oligonucleotides, etc. (for example see Sambrook, Maniatis and Fritsch). Naturally occurring mutations can also be isolated from cell populations (for example see Sambrook, Maniatis and Fritsch).

A “peptide” refers to a molecule containing at least 2 amino acids joined by a peptide bond. A “polypeptide” refers to a molecule containing at least 10 amino acids joined by peptide bonds and a “protein” refers to a molecule containing at least 20 amino acids.

A “polynucleotide encoding a nonfunctional mutant form of BORIS” refers to any polynucleotide having at least 50%, 60% or 70% sequence identity with the human (SEQ ID NO: 1) or mouse (SEQ ID NO: 3) BORIS polynucleotide, more likely 75%, 80%, 90%, 95% or 96%, 97%, 98% or 99% sequence identity with the human (SEQ ID NO: 1) or mouse (SEQ ID NO: 3) BORIS polynucleotide.

A “nonfunctional mutant BORIS peptide, polypeptide or protein” refers to a BORIS molecule that fails to perform any one of the critical activities of the wildtype BORIS molecule such as DNA binding, re-establishment of the paternal DNA-methylation pattern, etc. The “nonfunctional mutant BORIS peptide, polypeptide or protein” has at least 50%, 60% or 70% sequence identity with the human (SEQ ID NO: 2) or mouse (SEQ ID NO: 4) BORIS peptide, polypeptide or protein, more likely 75%, 80%, 90%, 95% or 96%, 97%, 98% or 99% sequence identity with the human (SEQ ID NO: 2) or mouse (SEQ ID NO: 4) BORIS peptide, polypeptide or protein.

A nonfunctional mutated BORIS molecule is recognized as a non-self antigen expressed only in transformed tumor cells and is used as an antigen to overcome the limitations of the prior art. The mutant form of BORIS is used as an ideal non-toxic vaccine, because it should not have any undesirable side effects caused by its DNA-binding activity and/or native function. In other words, the mutant BORIS used for vaccination has no functional activity and is present only as an immunogen (antigen). Unlike other tumor-specific antigens, BORIS is not expressed in the normal tissues in women. Furthermore, even though BORIS is expressed during the pubertal development of the normal testis in men, introduction and/or expression of a nonfunctional mutant BORIS should not be harmful, because the testis is an immune-privileged tissue (inaccessible for immune cells). In other words, the anti-BORIS immune response generated after immunization is not dangerous for normal cells and a BORIS vaccine does not induce autoimmunity. In addition, generation of a potent immune response is guaranteed because BORIS, unlike other tumor-specific antigens, is recognized as a foreign antigen. BORIS specific T cells are not deleted in thymus and recognize mutant BORIS as a non-self antigen and generate an immune response.

In one embodiment cDNA encoding mouse (mBORIS) BORIS is generated by RT-PCR on mRNA isolated from mouse or human testis. The DNA binding domain of the molecule is deleted and substituted with a small spacer known to work well in creating single chain Fv domain antibodies. The correct sequence is confirmed by automated nucleotide sequence analysis. The resulting molecule lacks the 11 ZF domains and consists of the N terminal region of mBORIS (amino acids 1-258) linked to the C terminal region (amino acids 573-636) through an 18-amino acid spacer.

The mutated cDNA is cloned into a pORF vector under control of the hEF1-HTLV promoter, however other expression vectors can be used. Here, the mutated cDNA is operably linked to a promoter and/or regulatory molecules that are capable of causing expression in the host cell. Viral vectors can be used including α-virus DNA or RNA vectors, adenoviruses and retroviruses (see Vasilevko, V. et al. (2003) Clin. Exp. Metastas. 20:489-98.; Leitner, W. W. et al. (2003) Nat Med 9:33-39; Ribas, A et al. (2002) Curr. Gene Ther 2:57-78).

In addition to the above, the invention encompasses using viral like particles encoding nonfunctional mutant BORIS molecules such as those from adenovirus, human hepatitis B, human hepatitis C, vaccinia virus, polyoviurs, etc. Recombinant viral proteins from different viruses have the useful property of self-assembling into virus-like particles (VLPs). These particles contain no viral nucleic acids and are therefore non-replicative, non-infectious and retain conformationally correct antigenic epitopes. VLP production has been shown in many experimental systems, such as mammalian cells, baculovirus-infected insect cells, yeasts, E. coli, cell free systems and transgenic plants. Importantly, vaccination with VLPs generates production of not only humoral but also cellular immune responses. VLPs infect professional APCs and subsequently induce protective cellular immune responses, including CD4⁺Th1 (type of CD4⁺T cells that helps CD8⁺T cells) and CD8⁺ CTL responses. Thus, VLPs have clearly revealed an exceptional capacity to activate cellular immune responses (T cell responses). The potential use of VLPs as prophylactic vaccines is currently being assessed in a number of different clinical trials. Results from these trials have been encouraging with excellent tolerability and high immunogenicity reported in each trial. Generation of a VLPs vaccine composed of truncated BORIS antigen will promote the induction of strong cellular immune responses against cancer cells expressing this tumor associated antigen. Hepatitis B virus (HBV) core antigen (HBcAg) and VSV are examples of suitable VLPs.

To generate a more robust cellular immune response, the truncated or mutated mBORIS is fused with molecular adjuvants such as B7 costimulatory molecules, beta-defensin 2/3, MIP3α, IFNγ, cytokines, chemokines, etc. prior to cloning into the vector. Other suitable molecular adjuvants are listed in the Table below

XCL1 (Lymphotactin α, SCM-1α, ATAC) IL-1α, IL-1β XCL2 (Lymphotactin β, SCM-1β, ATAC) IL-2 CCL1 (I-309, TCA3) IL-3 CCL2 (MCP-1, MCAF, JE) IL-4 CCL3 (MIP-1,α MIP-1αS, LD78α) IL-5 LD78β (MIP-1αP) IL-6 LD78γ IL-7 CCL4 (MIP-1β) IL-9 CCL5 (RANTES) IL-10 CCL7 (MCP-3) IL-11 CCL8 (MCP-2) IL-12 CCL9 (MIP-1γ) IL13 CCL10 (CCF18) IL14 CCL11 (Eotaxin) IL-15 CCL12 (MCP-5) IL-16 CCL13 (MCP-4, CKβ10) IL-17 CCL15 (HCC-2, Lkn-1, MIP-5, CC-2, NCC-3, IL-18 MIP-1δ) CCL16 (NCC-4, LEC, HCC-4, LMC, Mtn-1, IL-21 LCC-1, CKβ12) CCL17 (TARC) IL-23 CCL18 (DC-CK1, PARC, MIP-4, AMAC-1, TNFα CKβ7) CCL19 (exodus-3, ELC, MIP-3β, CKβ11) TNFβ CCL20 (exodus-1, MIP-3α, LARC, ST38) IFNα CCL21 (exodus-2, SLC, 6-Ckine, TCA4, IFNβ CKβ9) CCL22 (MDC, ABCD-1, DC/B-CK) IFNγ CCL23 (MIP-3, MPIF-1, CKβ8-1) M-CSF CCL24 (MPIF-2, CKβ6, eotaxin-2) G-CSF CCL25 (TECK, Ckβ15) GM-CSF CCL26 (Eotaxin-3, MIP-4α) MIF CCL27 (ALP, Skinkine, ILC, ESkine, CTAK) CD46 (MCP) CXCL8 (IL-8) CD27 (T14, S152) CXCL9 (mig) CD54 (ICAM-1) CXCL10 (γIP-10, crg-2) CD80 (B7-1, BB1) CXCL11 (H174, β-R1, I-TAC, IP-9) CD86 (B7-2, B70) CXCL12 (SDF-1α, SDF-1β, PBSF) CD134 (FLT3, STK-1) CXCL13 (BLC, BCA-1) CDw137 (4-1BB) CXCL14 (BRAK, bolekine) CDw150 (SLAM, IPO3) CX₃CL1 (Fractalkine, neurotactin) CD153 (CD30L) Defensin (DFα, DFβ) CD161 (NKR-P1A)

Alternatively, conventional adjuvants can be used such as Tween 80, 5% ethanol and Bupivacaine for DNA immunization. Other examples of conventional adjuvants include mineral salts (such as aluminium hydroxide and aluminium phosphate gels), oil emulsions and surfactant based formulations such as MF59, QS21, AS08 [SBAS2] (oil-in-water emulsion+MPL+QS21), Montanide ISA-51 and ISA-720, particulate adjuvants such as virosomes, AS04 ([SBAS4] Al salt with MPL), ISCOMS, polylactide co-glycolide (PLG), microbial derivatives (natural and synthetic) including monophosphoryl lipid A (MPL), Detox (MPL+M. Phlei cell wall skeleton), AGP[RC-529], DC_Chol, OM-174 (lipid A derivative), CpG motifs, modified LT and CT (genetically modified bacterial toxins), endogenous immunomodulators such as GM-CSF, IL-12, Immudaptin, as well as all other chemokines, cytokines and costimulatory molecules listed in the table above and inert vehicles, such as gold particles.

Adjuvants can be either mixed with the polypeptide encoding a nonfunctional mutant form of the Brother of Regulator of Imprinted Sites (BORIS) protein, polypeptide or peptide, a nonfunctional mutant BORIS protein, polypeptide or peptide and a dendritic cell expressing a nonfunctional mutant BORIS peptide, polypeptide or protein

Additional peptide molecules can be included in the nonfunctional mutant BORIS constructs to enhance/promote presentation of the nonfunctional mutant BORIS by the professional antigen presenting cells (APC) cells of the MHC class pathway. One example of this is a construct made with the peptide transducing domain (PTD). In general, an immune response relies on native antigen processing and presentation. The tumor-associated antigens can be expressed in bacteria, yeast or mammalian cells, however protein antigens expressed in those systems likely will not maximally stimulate T cell responses (either CTL responses or Th1-biased responses) since the soluble exogenous proteins are processed mainly by the MHC class II pathway. In fact, many anti-tumor vaccines rely on the induction of CD8+ CTL, but this usually requires that the protein is synthesized within the cytosol of APC. Unfortunately, in general the plasma membranes of eukaryotic cells are impermeable to the majority of proteins. It has recently been shown, however, that foreign proteins fused with the protein-transducing domain (PTD) can penetrate the plasma membrane, allowing the proteins to accumulate within the cells. This enhances the presentation of foreign peptides by the MHC class I molecules of APCs to the antigen-specific CD8+ T cells.

Vaccination/Immunization

Vaccine formulations of the present invention comprise an immunogenic amount of a polynucleotide encoding a nonfunctional mutant BORIS protein, polypeptide or peptide, a nonfunctional mutant BORIS protein, polypeptide or peptide or a dendritic cell expressing a nonfunctional mutant BORIS protein, polypeptide or peptide in combination with a pharmaceutically acceptable carrier. Mimeotopes, which are polypeptides of unrelated sequence but with a 3-dimensional structure corresponding to the nonfunctional mutant BORIS protein, polypeptide or peptide and that immunologically function in an identical manner can be used Mimeotopes, which are any biological molecule that is unrelated to BORIS structure, but has identical 3-d antigenic epitope/s and can be recognized by anti-BORIS T cells.

An “immunogenic amount” is an amount of the polypeptide encoding a nonfunctional mutant BORIS protein, polypeptide or peptide, nonfunctional mutant BORIS protein, polypeptide or peptide or a dendritic cell expressing a nonfunctional mutant BORIS protein, polypeptide or peptide sufficient to evoke an immune response in the subject to which the vaccine is administered The amount administered is an amount that induces a desired immune response, and the desired degree of protection Exemplary pharmaceutically acceptable carriers include, but are not limited to, sterile pyrogen-free water and sterile pyrogen-free physiological saline solution.

The vaccine formulations of the present invention are suitable for patients diagnosed with having at least one type of cancer including, but not limited to, breast, prostate, ovarian, gastric, liver, endometrial, glioma, colon, and esophageal cancer. The vaccine formulations of the present invention are also suitable for patients known to have a genetic susceptibility to cancer. In addition, the vaccine formulations of the present invention are suitable for the general population at large, including those without cancer or without a genetic susceptibility to cancer, who wish to invoke protection against contracting at least one type of cancer that expresses the wildtype BORIS protein, polypeptide or peptide.

Administration of the vaccine formulation may be carried out by any suitable means, including parenteral injection (such as intraperitoneal, subcutaneous, or intramuscular injection), intradermal, intravenous, nasal, rectal, vaginal or to an airway surface. Topical application of the virus to an airway surface can be carried out by intranasal administration (e.g. by use of dropper, swab, or inhaler which deposits a pharmaceutical formulation intranasally). Topical application of the virus to an airway surface can also be carried out by inhalation administration, such as by creating respirable particles of a pharmaceutical formulation (including both solid particles and liquid particles) containing the replicon as an aerosol suspension, and then causing the subject to inhale the respirable particles. Methods and apparatus for administering respirable particles of pharmaceutical formulations are well known, and any conventional technique can be employed. An “immunogenic amount” is an amount of the replicon particles sufficient to evoke an immune response in the subject to which the vaccine is administered.

When RNA or DNA is used as a vaccine, the RNA or DNA can be administered directly using techniques such as delivery on gold beads (gene gun), delivery by liposomes, or direct injection, among other methods known to people in the art. Any one or more constructs or replicating RNA can be use in any combination effective to elicit an immunogenic response in a subject. Generally, the nucleic acid vaccine administered may be in an amount that will induce a desired immune response, and the degree of protection desired. Precise amounts of the vaccine to be administered may depend on the judgment of the practitioner and may be peculiar to each subject and antigen.

The vaccine may be given in a single dose schedule, or preferably a multiple dose schedule in which a primary course of vaccination may be with 1-10 separate doses, followed by other doses given at subsequent time intervals required to maintain and or reinforce the immune response, for example, at 1-4 months for a second dose, and if needed, a subsequent dose(s) after several months. Examples of suitable immunization schedules include: (i) 0, 1 months and 6 months, (ii) 0, 7 days and 1 month, (iii) 0 and 1 month, (iv) 0 and 6 months, or other schedules sufficient to elicit the desired immune responses expected to confer protective immunity, or reduce disease symptoms, or reduce severity of disease.

Human (hBORIS) can be isolated from human testis and manipulated in the same manner. Likewise, BORIS can be isolated from the testis of any mammal or vertebrate and used similarly.

EXAMPLES 1. Generation of a Plasmid Encoding the ZF Deleted Form of the mBORIS Molecule Under the hEF1-HTLV Promoter

An RT-PCR reaction is performed using poly-A RNA from mouse testis and the following primers:

MB1F (SEQ ID NO: 5) 5′-CGTCACCATGGCTGCCGCTGAGGTCCCTG MB1R (SEQ ID NO: 6) 5′-AAGCTTCTGAAAGCTCTGAGGCTTTCCCTTGG MB2F (SEQ ID NO: 7) 5′-GGATCCGAGACGTTAGCCCCCAACAAGGACAGG MB2R (SEQ ID NO: 8) 5′-GAATTCTCACTTATCCATCATGTTAAAGATCATCTCGCAGG SpF (SEQ ID NO: 9) 5′-AGCTTGGTGGAGGCGGTTCAGGCGGAGGTGGCTCTGGCGGTGGCGGA TCGG SpR (SEQ ID NO: 10) 5′-GATCCCGATCCGCCACCGCCAGAGCCACCTCCGCCTGAACCGCCTCC ACCA

The PCR conditions are: 94° C. for 30 s, 60° C. for 30 s, 72° C. for 2 min Thirty (30) cycles are performed.

The PCR products are subcloned into the PCRII-TOPO cloning vector (Invitrogen). The C-terminal cDNA in PCRII-TOPO is restricted with BamHI enzyme and positive clones containing the insert are pooled and subsequently restricted with HindIII enzyme. Spacer primers (SpF and SpR) are annealed to create overhanging sticky ends and ligated into the BamHI-HindIII restricted vector. The N-terminal encoded fragment is restricted with HindIII and the inserts which are now separated from the vector are pooled and ligated into a HindIII digested construct containing the C-terminus and spacer. Clones with the proper orientation are then selected, sequenced (see, for example, the sequence for the ZF deleted BORIS molecule below) and subcloned into the pORF plasmid under control of the hEF1-HTLV promoter (Invivogen).

CHO cells are transfected with the resulting construct using standard molecular techniques (Sambrook J, Fritsch E F and Maniatis T (1989) Molecular Cloning: A Laboratory Manual, Cold Spring Harbor; incorporated herein by reference)

The expression of the zinc finger deleted mBORIS construct is analyzed by Northern blots of mRNA isolated from transfected CHO cells using standard molecular technique (Sambrook et al., 1989).

2. Immunization of Mice with DNA Encoding the ZF Deleted Form of the Boris Molecule

The plasmid encoding the ZF deleted mBORIS construct is isolated using the EndoFree Plasmid maxi kit (Qiagen). Purity of the plasmid DNA was confirmed by UV spectrophotometry (260 nm/280 nm absorbance ratio>1.7) and gel electrophoresis.

Gold beads are coated with DNA (1 μg/0.5 mg gold) and 5-7 weeks old Balb/c mice are immunized using the Helios Gene Gun. Mice are boosted in the same way, three times bi-weekly Ten days after the last boost, the mice are bled and challenged with 1.0×10⁴ or 1.0×10⁵ 4T1 breast cancer cells. The tumor size is measured everyday or every two-three days using calipers.

3. Protective Studies

Immunization of Mice with Plasmid Vaccine:

One example of a preventive anti-cancer vaccine approach is the use of DNA encoding a deleted form of the mouse BORIS molecule that lacks the zinc finger domains and therefore the DNA binding property.

Purified plasmid is used to coat gold beads (2 μg plasmid/0.5 mg gold particles) as was we described earlier (Ghochikyan et al. (2003) Eur J Immunol 33:3232-41). Immunizations of BALB/c mice with plasmid is performed on shaved abdominal skin using the Helios gene gun (Bio-Rad, Hercules, Calif.) as described by Ross et al. (2000, Nat. Immunol 1:127-131). Briefly, mice are bombarded 3 times with doses containing 2 μg of DNA per 0.5 mg of ˜1 μm gold beads (DeGussa-Huls Corp., Ridefield Park, N.J.) at a helium pressure setting of 400 psi. Mice are immunized and boosted by the same method biweekly and challenged with two different doses of 4T1 breast cancer cells (10⁵ or 10⁴) ten days after the last boost as described (Vasilevko et al., 2003). Different groups of mice are immunized with plasmid encoding a modified BORIS molecule mixed with DNA encoding a certain molecular adjuvant(s) (see Table 1 for details). Such molecular adjuvants are known to increase cellular immune responses to the different antigens.

TABLE 1 Mice were immunized five times biweekly using a BORIS protective vaccine (pORF-mBORIS) mixed with pORF-mGMCSF (encoding mouse GMCSF), pORF-mIFNγ (encoding mouse IFNγ), or pORF-mIL12 + pIRES-mIL18 (two plasmids encoding mouse IL12 and IL18, accordingly). After the last boost, mice are challenged with 10⁵ or 10⁴ 4T1 mouse breast cancer cells that expressed the modified BORIS molecule. Groups Immunogen Molecular Adjuvant Challenge with 4T1 cells 1 pBORIS pGM-CSF 10⁵ 2 pBORIS pIFNγ 10⁵ 3 pBORIS pIL12/IL18 10⁵ 4 Vector — 10⁵ 5 — pIL12/IL18 10⁵ 6 pBORIS pIL12/IL18 10⁴ 7 Vector — 10⁴ 8 — pIL12/IL18 10⁴

Generation of Adenoviral Vector Encoding the ZF Deleted Form of Mouse BORIS Molecule (Ad5-BORIS) and Immunization of Mice

Ad5-BORIS recombinant adenovirus is prepared using AdEasy XL Adenoviral Vector System from Stratagene. The shuttle vector is constructed by subcloning the ZF-deleted mBORIS fragment into the plasmid pShuttle-CMV. For this purpose the BORIS fragment is synthesized by PCR using pORF-mBORIS plasmid as a template and the following primers:

SalI-MB-F (SEQ ID NO: 11) 5′-ACGCGTCGACATGGCTGCCGCTGAGGTCCCTGTCCCTTCTGGG NotI-MB-R (SEQ ID NO: 12) 5′-CGGCCGTCACTTATCCATCATGTTAAAGATCATCTCGCAGG

The PCR product is subcloned into the PCR4-TOPO cloning vector (Invitrogen). BORIS fragment is restricted using SalI and NotI restriction endonucleases. The resulting product is purified on an agarose gel and subcloned using SalI-NotI cloning sites into the pShuttle-CMV vector.

The in vitro expression of ZF-deleted mBORIS is analyzed in CHO cells by immunoblotting as shown in FIG. 6. The shuttle vector carrying the deleted BORIS is linearized with PmeI and purified on an agarose gel. Electroporation competent cells BJ-5183-Ad-1 are transformed with Pme-digested pShuttle-mBORIS plasmid to produce the recombinant Ad plasmid. AD-293 cells are transfected with selected recombinant Ad-BORIS DNA and primary viral stocks are prepared. The primary viral stock resulting (10⁷ pfu/ml) is amplified in AD-293 cells and then purified on a CsCl gradient. The purified virus is dialyzed against PBS-5% sucrose and used for immunization of mice.

Balb/c mice immunized with pBORIS four times biweekly boosted once. i.m. with Ad5-BORIS (10⁹ PFU). Control animals injected with vectors are boosted with Ad5. Ten days after the last boost mice are challenged with two different doses of 4T1 breast cancer cells (10⁵ and 10⁴) as described (Vasilevko et al., 2003).

Tumor Cell Lines

Mammary tumor cell lines provided by Dr. F. Miller (Karmanos Cancer Institute, Detroit, Mich.) are used. 4T1.2 cells are a thioguanine-resistant variant derived from 410.4 cells (a mammary tumor cell line originally isolated from a single spontaneously arising mammary tumor in a BALB/c fC3H mouse) without mutagen treatment. The cells are cultured (37° C., 10% CO₂) in Dulbecco-modified Eagle's essential medium (DMEM) containing low glucose and supplemented with 5% fetal bovine serum, 5% newborn calf serum, 2 mM glutamine, 100 units/ml penicillin, 100 μg/ml streptomycin, 0.1 mM non-essential amino acids and 1 mM sodium pyruvate (D10) (Life Technologies, Inc.).

Determination of Tumor Volumes

Tumor volumes are determined daily by two-dimensional measurement and calculation using the formula L×(W²)/2, where L represents the length and W the width of the tumor. The experiments are terminated when the mouse appears moribund or the tumor reaches approximately 1.5 cm³ for experiments involving a challenge with 10⁴ cells and 2 cm³ for experiments involving a challenge with 10⁵ 4T1 cells.

The time of appearance (latency period) is designated as the time elapsed before a tumor with a volume in excess of 0.1 cm³ is present. To determine tumor growth rate, scatter plots are analyzed in the near linear periods of tumor growth.

Statistical Analysis

Results on the average times of appearance of tumor nodules (latency period) and growth of tumor (tumor volume), as well as survival times are examined using an analysis of variance (ANOVA) and Tukey multiple comparisons post-test. Mean and standard deviation (SD) is calculated using GraphPad Prism 3.0 Software.

4. Immunology

B and T cell immune responses against BORIS are analyzed using two different immunization protocols.

1. Preparation of Mouse BORIS Proteins and Immunization of Mice.

The ZF-deleted fragment of mouse BORIS is subcloned into the bacterial expression vector pET24d(+) by using NcoI-XhoI cloning sites in frame with a C-terminal 6H is tag. Both sites are introduced and a stop codon is removed during the PCR step of cloning. In addition, plasmids encoding the deleted BORIS molecule fused with a Protein Transduction Domain (PTD) are constructed. The HIV-Tat protein transduction domain (Tat₄₇₋₅₇ YGRKKRRQRRR) (SEQ ID NO: 13) is fused to the N-terminal end of the deleted BORIS via PCR and then cloned into the pET24d(+) vector NcoI-XhoI cloning sites. An E. coli BL21(DE3) strain transformed with the resultamt pET-mBORIS or pET-TATmBORIS plasmids, is grown in LB with kanamycin at 28° C. until an A₆₀₀ 0.8 is reached. Protein synthesis is induced by the addition of IPTG at a final concentration of 1 mM. The cells are harvested three to five hours later by centrifugation and used for protein purification by affinity chromatography on a nickel-NTA (nitrilotriacetic acid) column (Qiagen), as illustrated in FIG. 7.

In addition, the ZF-deleted fragment of BORIS fused with PTD is subcloned into the yeast expression vector pGAPZalpha in frame with signal sequence into EcoRI-XbaI cloning sites. Both sites are introduced and the ATG initiation codon is removed during the PCR step of cloning. Pichia pastoris X33 strain is transformed by electroporation with pGAPZ-BORIS linearized with the AvrII restriction enzyme and positive clones are selected on YPD media containing 100 μg/ml Zeocin. For expression analysis, selected positive clones are grown in YPD/Zeocin broth and expression analyzed in supernatant at different time points by immunoblotting.

2. Immunization of Mice with Dendritic Cells (DC).

Primary bone marrow DCs are obtained from mouse bone marrow precursors as follows. Erythrocyte-depleted murine bone marrow cells harvested from femurs and tibias are plated in completed RPMI-10 media supplemented with recombinant murine GM-CSF (100 U/ml). On day 3, nonadherent granulocytes are gently removed and fresh media is added. Nonadherent DC are harvested at day 7 and purified by positive selection kit (Miltenyi) using CD11c Microbeads.

DC harvested at day 7 of culture and purified by positive selection are infected with Ad5-BORIS by incubation at 10⁷ cells/ml in RPMI 1640 at a multiplicity of infection of 1000-2000. After 1 h, complete medium is added to dilute the DC to a final concentration of 1×10⁶ to 2×10⁶ cells/ml. Cells are harvested 24 h later, extensively washed in order to discard any carryover of adenoviral particles, and used for immunization. In addition, DC that are harvested at day 7 of culture and purified by positive selection are incubated with 10 μg/ml ZF-deleted mBORIS protein at 37° C., 5% CO₂ for 24 hours, washed twice with PBS. Protein uptake by DC is analyzed in aliquots by Flow cytometry using anti-mouse BORIS antibodies and appropriate secondary antibodies labeled with FITC. Balb/c mice are immunized i.p. three times every three weeks with 1×10⁶ DC and T cell responses are analyzed 10 days after the last boost in the cultures of splenocytes culture.

5. Results Immunization Results are Presented in FIGS. 1-4.

DNA encoding a mutant form of the cancer-specific mouse BORIS antigen lacking DNA-binding function (deleted 11-Zinc Fingers) was constructed using the mammalian expression vectors pORF (Invivogen) and the AdEasy XL Adenoviral Vector System (Stratagene). These vaccines have been used as a prophylactic anti-cancer vaccine in a mouse breast cancer model. In this model we used BALB/c mice (H-2d haplotype) and the 4T1 native mammary tumor cell line, which is a thioguanine-resistant variant derived from 410.4 cells without mutagen treatment. Importantly, these mouse breast cancer cells are expressing the full mouse BORIS molecule as we demonstrated by RT-PCR. Therefore this is an ideal model for examination of ability of the BORIS molecule to be used as a protective cancer vaccine.

Two different types of experiments were conducted. The first type of experiments included a group of mice that were vaccinated with pBORIS (plasmid encoding deleted mouse BORIS molecule) mixed with DNA encoding different mouse cytokines (pGM-CSF; pIL12/IL18; pIFNγ) as molecular adjuvants. Mice were injected with vector (pORF) or pIL12/IL18 as controls. Mice were immunized and boosted using a gene gun technique and then were challenged with 10⁴ or 10⁵ 4T1 cells.

The second type of experiment included a group of mice that were vaccinated with pBORIS and boosted with replication defective adenoviral vector (Ad5) that was modified to express the ZF deleted mouse BORIS molecule (Ad5-BORIS). A group of mice injected with vector and boosted with Ad5 was used as a control. The animals were challenged with 10⁴ or 10⁵ 4T1 cells and tumor appearance and growth were analyzed. We note that it had previously been found that injection of as few as 10⁴ 4T1.2 cells into the mammary glands of BALB/c mice resulted in local growth of mammary tumors in 100% of challenged animals.

Vaccination with pBORIS plus pIL12/IL18 or pBORIS followed by Ad5-BORIS resulted in protection of mice from challenge with 10⁴ unmodified 4T1 tumor cells. Although 50% of the mice from the group immunized with pBORIS mixed with pIL12/IL18 generated small tumors (0.2-0.4 cm³), they all survived by day 39. All experimental mice died approximate 10 days earlier.

The results for mice vaccinated with Ad5-BORIS were more extreme. On day 24, when mice in the control groups died from tumor growth, 100% of the mice immunized with the Ad5-BORIS vaccine were not only alive, but did not generate tumors at all. In fact they did not generate tumors at least till day 33 after the challenge. These results indicate that the ZF deleted BORIS vaccine effectively protected animals from a challenge with 10⁴ mammary tumor cells.

A second set of experiments was conducted using more stringent conditions and challenging mice with 10⁵ 4T1 tumor cells. Vaccination with the plasmid pBORIS plus pIFNγ or pIL12/IL18 significantly prolonged the time of tumor growth to a volume of 2 cm³ and increased the survival of the BALB/c mice. The vaccination also lowered the tumor growth rate in mice that were challenged with 10⁵ 4T1 tumor cells. A more profound effect was detected in mice vaccinated with pBORIS and boosted with Ad5-BORIS before challenge with 10⁵ unmodified 4T1 cells. Here, on day 23, when all mice in the control group had died from tumor growth, 80% of the mice immunized with Ad5-BORIS were alive and surviving animals had significantly smaller sized tumors.

Separate groups of BALB/c mice were immunized with deleted mouse BORIS protein purified from E. coli system. Here, five mice were injected subcutaneously with protein (50 ug/mouse) mixed with Quil A Th1-type conventional adjuvant (Sigma). After 4 immunizations all animals induced significant titer of anti-BORIS antibodies. Another group of 5 mice were simultaneously immunized i/p with isolated dendritic cells infected with Ad5-BORIS. After 3 injections, the mice generated T cell responses against mBORIS that were detected in vitro in the culture of splenocytes activated with mBORIS protein. Therefore, immunization with BORIS induces B and T cell immune responses in mice and these immune responses are protecting the animal from challenge.

6. Truncated BORIS Attached to the PTD as a Subunit Vaccine

A PTD is attached to a nonfunctional truncated or mutant BORIS protein and the fusion product generated in a yeast expression system. Genes encoding PTD and a nonfunctional mutant BORIS are subcloned into a yeast expression vector such as pGAPZα. The expressed and secreted protein is purified using standard molecular techniques. Mice are immunized with the antigen formulated in two different conventional adjuvants and immune responses as well as protection to the tumor antigen analyzed.

7. Virus-Like Particles Encoding a Nonfunctional Mutant BORIS as a Subunit Vaccine

A VLP-BORIS subunit vaccine based on Hepatitis B virus (HBV) core antigen (HBcAg) is generated. This antigen self-assembles into VLPs after expression in yeast cells. Foreign sequences can be inserted into several regions of the HBcAg without disrupting the assembly process. Accordingly, a chimeric HBcAg-BORIS particle is generated that is used for immunization of mice.

8. Analysis in BALB/c and p53 KO Mice

Immune responses in BALB/c mice without challenge and in young p53 knockout mice that are not developing tumors in that age are analyzed. Both humoral and cellular immune responses in mice immunized with different BORIS vaccines are determined. Sera from immunized mice is analyzed for detection of anti-BORIS antibody production during a 3 month experimental period. CD4+ and CD8+ T cell proliferation and activation of T regulatory cells before and after the challenge of BALB/c mice is determined. Simultaneously, activation of NK cells that could directly kill mammary tumor cells is analyzed. Functional activity of BORIS-specific cytotoxic T lymphocytes (CTL) before and after challenge with mammary tumor 4T1 cells is demonstrated. P815 tumor cells that naturally express wildtype BORIS molecules are used as target cells along with 4T1 cells for detection of NK and CTL activity

ADDITIONAL REFERENCES

-   Filippova, G. N. et al. Tumor-associated Zinc Finger Mutations in     the CTCF Transcription Factor Selectively Alter Its DNA-binding     Specificity. Cancer Research 62:48-52 (2002). -   Kim, J. J. et al. In vivo engineering of a cellular immune response     by coadministration of IL-12 expression vector with a DNA     immunogen. J. Immunol 158:816-826 (1997). -   Kim, J. J. et al. CD8 positive T cells influence antigen-specific     immune responses through the expression of chemokines. Journal of     Clinical Investigation 102:1112-24 (1998). -   Kim, J. J. et al. Modulation of amplitude and direction of in vivo     immune responses by co-administration of cytokine gene expression     cassettes with DNA immunogens. European Journal of Immunology     28:1089-1103. (1998). -   Kim, J. J. et al. Intracellular adhesion molecule-1 modulates     beta-chemokines and directly costimulates T cells in vivo. Journal     of Clinical Investigation 103:869-77 (1999). -   Kim, J. J. et al. Macrophage Colony-Stimulating Factor Can Modulate     Immune Responses and Attract Dendritic Cells in Vivo. Human Gene     Therapy 11:305-321 (2000). -   Lutz, M. B. et al. An advanced culture method for generating large     quantities of highly pure dendritic cells from mouse bone marrow.     Immunol. Meth. 223:77-92 (1999). -   Nardelli, B. & Tam, J. P. The MAP system. A flexible and unambiguous     vaccine design of branched peptides. Pharm Biotechnol. 6:803-819     (1995). -   Resko, J. E. J. et al. Cell Growth Inhibition by the Multivalent     Transcription Factor CTCF. Cancer Research 61:6002-7 (2001). -   Ribas, A., Butterfield, L. H., Glaspy, J. A. & Economou, J. S.     Cancer Immunotherapy Using Gene-modified Dendritic Cells. Curr. Gene     Ther 2:57-78 (2002). -   Ross, R. M., Xu, Y., Bright, R. A. & Robinson, H. L. C3d enhancement     of antibodies to hemagglutinin accelerates protection against     influenza virus challenge. Nat. Immunol. 1, 127-131 (2000). -   Smith, M., Burchell, J. M., Graham, R., E. P., C. & J., T.-P.     Expression of B7.1 in a MUC1-expressing mouse mammary epithelial     tumour cell line inhibits tumorigenicity but does not induce     autoimmunity in MUC1 transgenic mice. Immunol. 97, 648-655 (1999).

The invention being thus described, it will be apparent to one of ordinary skill in the art that various modifications of the materials and methods for practicing the invention can be made. Such modifications are to be considered within the scope of the invention as defined by the following claims.

Each of the references from the patent and periodical literature cited herein is hereby expressly incorporated in its entirety by such citation. 

1. An immunogenic composition comprising nonfunctional Brother of Regulator of Imprinted Sites (BORIS) protein, polypeptide or peptide, wherein said nonfunctional protein, polypeptide or peptide does not bind DNA.
 2. The composition according to claim 1, wherein said nonfunctional BORIS protein, polypeptide or peptide comprises SEQ ID NO:2, lacking all zinc finger domains.
 3. (canceled)
 4. The composition according to claim 1, wherein said nonfunctional BORIS protein, polypeptide or peptide is attached to a pharmaceutically accepted carrier.
 5. The composition according to claim 1, wherein said nonfunctional BORIS protein, polypeptide or peptide is attached to a protein transducing domain.
 6. The composition according to claim 1, wherein said BORIS protein, polypeptide or peptide is attached to a peptide that enhances said nonfunctional BORIS protein, polypeptide or peptide antigenicity or immunogenicity.
 7. The composition according to claim 1, further comprising a bacterial, mammalian or yeast cell, or virus.
 8. (canceled)
 9. (canceled)
 10. The composition according to claim 1, further comprising an adjuvant.
 11. The composition according to claim 10, wherein said adjuvant is mixed with or fused to said nonfunctional BORIS protein, polypeptide or peptide.
 12. The composition according to claim 10, wherein said adjuvant is selected from the group consisting of a cytokine, a chemokine and a costimulatory molecule.
 13. (canceled)
 14. (canceled)
 15. (canceled)
 16. The composition according to claim 7, wherein said mammalian cell is a dendritic cell.
 17. An antibody comprising a binding site that recognizes an epitope from a nonfunctional Brother of Regulator of Imprinted Sites (BORIS) protein, polypeptide or peptide.
 18. A immunotherapeutic composition against cancer comprising a nonfunctional Brother of Regulator of Imprinted Sites (BORIS) protein, polypeptide or peptide wherein said nonfunctional BORIS protein, polypeptide or peptide does not bind DNA.
 19. (canceled)
 20. The immunotherapeutic composition according to claim 18, wherein said nonfunctional BORIS protein, polypeptide or peptide comprises SEQ ID NO:2, lacking all zinc finger domains.
 21. The immunotherapeutic composition according to claim 18, further comprising an adjuvant.
 22. The immunotherapeutic composition according to claim 18, further comprising a pharmaceutically acceptable carrier.
 23. A method of immunizing a mammalian subject which comprises administering to a patient in need thereof an effective amount of a nonfunctional Brother of Regulator of Imprinted Sites (BORIS) protein, polypeptide or peptide, wherein said nonfunctional BORIS protein, polypeptide or peptide lacks all zinc finger domains.
 24. The method of claim 23, wherein said a nonfunctional BORIS protein, polypeptide or peptide is mixed or fused with a molecular adjuvant.
 25. The method of claim 24, wherein said molecular adjuvant is a molecule that increases cellular immune response and/or antibody responses.
 26. The method of claim 24, wherein said molecular adjuvant is selected from the group consisting of any cytokine, chemokine, and costimulatory molecule.
 27. The method of claim 23, wherein said nonfunctional BORIS protein, polypeptide or peptide is mixed with any conventional or molecular adjuvant.
 28. The method of claim 23, wherein said nonfunctional BORIS protein, polypeptide or peptide is attached to a pharmaceutically accepted carrier.
 29. The method of claim 23, wherein said nonfunctional BORIS protein, polypeptide or peptide is attached to a peptide that enhances its antigenic or immunogenic property.
 30. The method of claim 23, wherein said nonfunctional BORIS protein, polypeptide or peptide further comprises a protein transducing domain (PTD).
 31. The method of claim 46, wherein said dendritic cell presents the nonfunctional BORIS protein, polypeptide or peptide after being transfected with DNA encoding the BORIS molecule which comprises SEQ ID NO:2, lacking all zinc finger domains.
 32. The method of claim 46, wherein said dendritic cell presents the nonfunctional BORIS protein, polypeptide or peptide after being infected with a viral vector encoding the nonfunctional BORIS molecule which comprises SEQ ID NO:2, lacking all zinc finger domains.
 33. The method of claim 46, wherein said dendritic cell presents the nonfunctional BORIS protein, polypeptide or peptide after being loaded with the BORIS protein, polypeptide, or peptide which comprises SEQ ID NO:2, lacking all zinc finger domains, or any modified protein form of BORIS.
 34. The method of claim 23, wherein said administration occurs intramuscularly, subcutaneously, intradermally, intravenously, nasally, rectally, vaginally or peritoneally.
 35. The method according to claim 23, wherein said patient has more than one type of cancer.
 36. The method of claim 23, wherein said patient has cancer.
 37. (canceled)
 38. The method according to claim 23, wherein said patient has a genetic susceptibility to cancer.
 39. (canceled)
 40. The method according to claim 23, wherein said immunization results from mounting a cellular immune response comprising T cells that recognize an epitope from a nonfunctional BORIS peptide, polypeptide, protein.
 41. A dendritic cell expressing a nonfunctional BORIS peptide, polypeptide, or protein.
 42. A dendritic cell loaded with a nonfunctional mutant BORIS peptide, polypeptide, or protein.
 43. The dendritic cell according to claim 41, wherein said cell is infected with a viral vector encoding a nonfunctional BORIS protein, polypeptide or peptide.
 44. A method of treating cancer comprising administering to a patient in need thereof an effective amount of an immunotherapeutic composition according to claim
 18. 45. The immunotherapeutic composition according to claim 18, further comprising a dendritic cell.
 46. The method of claim 23, further comprising a dendritic cell.
 47. The method of claim 23, wherein said cancer is breast or prostate cancer. 